41v ??

Hello all,

I was called out to a job where they are having some C-Bus issue.

The site is and office, about 10 years old and has got a combination of the old black boxes, green din rail and blue din rail C-Bus units.
Total of 56 units on the n/w including relays, dimmers switches and PIR's.

When I scanned the n/w I found that most of the 5751 PIR's have 41 Volt according to toolkit... I have not measured at the sensor itself yet.

When I isolated the switch board from the field, I measured with my meter the voltage. Field got 0V and cabinet got 34V.

There are intermitted issues on the network.

So far I just had a quick look onsite and will return at a later stage to fix the job.

I suspect that there are faulty units on the C-Bus and will do a process of elimination to find things.

Anyone seen something like this before?

Cheers,

Roeland

 

Hello Roeland.
Given the age and description of the hardware, I'd suspect you have at least some of the old style power supplies (5000PS?). These can do nasty things when they fail, including communication issues and higher network voltages, so I'd start there.

Mark